                ["<li id='ch-" ch-id "'>" ch-id ": " (:msgs ch-info) "</li>"]))
            (get actx-ch-ch-infos actx))
      "</ul></div>"
-     ["<ul>" (mapv (fn [child-actx]
-                     ["<li>" (vis-html-actx vis child-actx
-                                            actx-ch-ch-infos (:closed actx-info))
-                      "</li>"])
-                   (sort #(compare (last %1) (last %2)) (keys children)))
-      "</ul>"]
+     (when (not (:closed actx-info))
+       ["<ul>" (mapv (fn [child-actx]
+                       ["<li>" (vis-html-actx vis child-actx actx-ch-ch-infos)
+                        "</li>"])
+                     (sort #(compare (last %1) (last %2)) (keys children)))
+        "</ul>"])
      "</div>"]))
 
 ;; ------------------------------------------------

               (let [childy (actx-y (:child-actx delta))
                     ay (actx-y (:actx delta))
                     cy (ch-y (:ch delta))]
                 [(case (:delta delta)
                    :put (when (get chs (:ch delta))
                           ["<g transform='translate(500," ay ")'>"
                            "<line class='delta' x1='0' y1='0' x2='100' y2='"
                            (- cy ay) "' stroke='green'"])
                    :take (when (get chs (:ch delta))
                            ["<g transform='translate(600," cy ")'>"
                             "<line class='delta' x1='0' y1='0' x2='-100' y2='"
                             (- ay cy) "' stroke='" (if (:msg delta) "green" "black") "'"])
                    :actx-start (when (> childy line-height)
                                  ["<g transform='translate(30," ay ")'>"
                                   "<line class='delta' x1='0' y1='0' x2='30' y2='"
                                   (- childy ay) "' stroke='green'"])
                    :actx-end (when (> childy line-height)
                                ["<g transform='translate(60," childy ")'>"
                                 "<line class='delta' x1='0' y1='0' x2='-30' y2='"
                                 (- ay childy) "' stroke='black'"])
                    nil)
                  " stroke-width='1' marker-end='url(#triangle)'/></g>"
                  (when (:ch-name delta)
                    ["<text class='ch-name' x='540' y='" (* 0.5 (+ ay cy))
                     "'>" (:ch-name delta) "</text>"])])))
           deltas)]))

;; ------------------------------------------------

          (when (< @event-delay 0) (<! step-ch)))
        (assign-positions @vis @root-actx vis-positions actx-ch-ch-infos nil)
        (set-el-innerHTML (str el-prefix "-html")
                          (apply str (flatten (vis-html-actx @vis @root-actx actx-ch-ch-infos))))
        (set-el-innerHTML (str el-prefix "-svg")
                          (apply str (flatten (vis-svg-actxs @vis @vis-positions deltas :curr))))
        (recur (inc num-events) @vis @vis-positions)))
    (ago world w
         (reset! root-actx world)
